How are you meant to bind to a uxcombobox?

Lets say I have an object "MyObject" which has a property "ItemID" which is a fk to a product table

I currently have the following xaml

        <Intersoft:UXComboBox Name="cboType"
                              ItemsSource="{Binding Source={StaticResource ProductSource}, Path=Items}"
                              DisplayMemberPath="ItemDesc"
                              SelectedValuePath="ItemID"
                              SelectedValue="{Binding MyObject.ItemID, Mode=TwoWay}"
                              />

The dropdown list is populated correctly and the binding appears to work from the combobox down to the object.  However, when the page loads the value is not changing the combobox.  I tried to do a test in code and it looks like setting the selectedvalue does not set the combobox display.  Is there another property I am meant to bind to?

Hue